CERN Accelerating science

CMS Note
Report number	CMS-CR-2009-114
Title	The CMS Online Cluster : IT for a Large Data Acquisition and Control Cluster
Author(s)	Gerry, Bauer (CERN) ; Beccati, Barbara (CERN) ; Behrens, Ulf (DESY) ; Biery, Kurt (Fermilab) ; Brett, Angela (Fermilab) ; Branson, James (UC, San Diego) ; Cano, Eric (CERN) ; Cheung, Harry (Fermilab) ; Ciganek, Marek (CERN) ; Cittolin, Sergio (CERN) ; Coarasa, Jose Antonio (CERN ; UC, San Diego) ; Deldicque, Christian (CERN) ; Dusinberre, Elizabeth (UC, San Diego) ; Erhan, Samim (UCLA, Crump Inst.) ; Fortes Rodrigues, Fabiana (CEFET, Rio de Janeiro) ; Gigi, Dominique (CERN) ; Glege, Frank (CERN) ; Gomez-Reino, Robert (CERN) ; Gutleber, Johannes (CERN) ; Hatton, Derek (DESY) ; Laurens, Jean-Francois (CERN) ; Loizides, Constantin (MIT) ; Lopez Perez, Juan Antonio (CERN) ; Meijers, Frans (CERN) ; Meschi, Emilio (CERN) ; Meyer, Andreas (CERN ; DESY) ; Mommsen, Remi (Fermilab) ; Moser, Roland (CERN) ; O'Dell, Vivian (Fermilab) ; Oh, Alexander (CERN) ; Orsini, Luciano (CERN) ; Patras, Vaios (CERN) ; Paus, Christoph (MIT) ; Petrucci, Andrea (UC, San Diego) ; Pieri, Marco (UC, San Diego) ; Racz, Attila (CERN) ; Sakulin, Hannes (CERN) ; Sani, Matteo (UC, San Diego) ; Schieferdecker, Philipp (CERN) ; Schwick, Christoph (CERN) ; Serrano Margaleff, Josep Francesc (MIT) ; Shpakov, Dennis (Fermilab) ; Simon, Sean (UC, San Diego) ; Sumorok, Konstanty (MIT) ; Zanetti, Marco (CERN)
Publication	2010
Imprint	18 May 2009
Number of pages	11
In:	J. Phys.: Conf. Ser. 219 (2010) 022002
In:	17th International Conference on Computing in High Energy and Nuclear Physics, Prague, Czech Republic, 21 - 27 Mar 2009, pp.022002
DOI	10.1088/1742-6596/219/2/022002
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; CMS
Free keywords	ACQUISITION ; TRIGGER ; COMPUTING
Abstract	The CMS online cluster consists of more than 2000 computers running about 10000 application instances. These applications implement the control of the experiment, the event building, the high level trigger, the online database and the control of the buffering and transferring of data to the Central Data Recording at CERN. In this paper the IT solutions employed to fulfil the requirements of such a large cluster are revised. Details are given on the chosen network structure, configuration management system, monitoring infrastructure and on the implementation of the high availability for the services and infrastructure.
Copyright/License	Preprint: (License: CC-BY-4.0)

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